ok, thank you, in my problem i want to solve the following equation
numericaly for b , t_n indicates the last value of t
(t_n*exp(-b*t_n)*sum_{i=1}^{n} f_i) / (1-exp(-b*t_n)) - (sum_{i=1}^{n}
(f_i*(t_i*exp(-b*t_i)-t_{i-1}*exp(-b*t_{i-1}))) /
(exp(-b*t_{i-1})-exp(-b*t_i)) ) = 0
b is then the mle.
jim holtman wrote:
> If you type
>
> t[0]
>
> you will get the value
>
> numeric(0)
>
> Which is a numeric vector of lenght 0; this is not the same a the
> value of 0.
>
> t[0] does not select any value. If you expect this to happen in your
> code, then check against it and assign whatever value you want:
>
> ifelse(length(t[i]) == 0, 0, t[i])
>
>
>
> On 1/14/06, *voodooochild at gmx.de <mailto:voodooochild at gmx.de>*
> <voodooochild at gmx.de <mailto:voodooochild at gmx.de>> wrote:
>
> Hello,
>
> i got an warning message in the following code:
>
> f<-1:100
> t<-1:100
> b<-100
>
> ll2 <- function(b,f,t) {
> t<-cumsum(t)
> tn<-t[length(t)]
> i<-seq(along=f)
> s1<-(tn*exp(-b*tn)*sum(f[i]))/(1-exp(-b*tn))
>
>
s2<-sum((f[i]*(t[i]*exp(-b*t[i])-t[i-1]*exp(b*t[i-1])))/(exp(-b*t[i-1])-exp(-b*t[i])))
>
> s1-s2
> }
>
> ll2(b,f,t)
>
> i think, the problem here is, that t[0] doesn't exist and so i got
> different length of objects. want can i do to avoid this error?
> the assumption is that t[0] should be 0.
>
> best regards
> andreas
>
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>
>
> --
> Jim Holtman
> Cincinnati, OH
> +1 513 247 0281
>
> What the problem you are trying to solve?